Geometric-invariant image watermarking by key-dependent triangulation

Abstract

Fast and massive dissemination of image data across the Internet imposes great challenges of protecting images against illegal access and unauthorized reproduction. Image watermarking provides a powerful solution for intellectual protection. In this paper, a new image watermarking approach robust to various geometric distortions is proposed. The new scheme involves detecting image feature points and triangulating them in a secure key-dependent manner. The neighborhood pixel ratio of gray-scale image is investigated in the paper. It is a novel robust image feature which can be seamlessly combined with the proposed key-dependent triangulation scheme. A random pre-warping framework is adopted to make the scheme robust to collusion attack. Our experiments demonstrate that the new scheme is robust to rotation, scaling, noise addition, JPEG compression, StirMark, shearing transformation, collusion, and other common attacks in both spatial and frequency domain.